Bricks

​The latest science, described in the World Bank report “Turn Down the Heat,” indicates that we are heading toward a 4° C warmer world, with catastrophic consequences in this century. While carbon dioxide (CO2) is still the No. 1 threat, there is another category of warming agent called short-lived climate pollutants (SLCPs). Mitigating these pollutants is a must if we want to avoid the 4° C warmer future.

The main SLCPs are black carbon, methane, tropospheric ozone, and hydrofluorocarbons. They are potentially responsible for more than one-third of the current warming. Because SLCPs have a much shorter lifetime in the air than CO2; reducing their emissions can create almost immediate reduction of global/regional warming, which is not possible by reducing CO2 emissions alone. According to one U.N. report, full implementation of 16 identified measures to mitigate SLCPs would reduce future global warming by about 0.5˚C.

In this blog, we will focus on one SLCP – black carbon. Black carbon is a primary component of particulate matter (PM), the major environmental cause of premature deaths globally. As a climate pollutant, black carbon’s global warming effects are multi-faceted. It can warm the atmosphere directly by absorbing radiation. When deposited on ice and snow, black carbon reduces their reflecting power and increases their melting rate. At the regional level, it also influences cloud formation and impacts regional circulation and rainfall patterns such as the monsoon in South Asia.

Dhaka. Chittagong. Khulna. Just a handful of cities where construction is booming. In Bangladesh, the construction sector is driven by a single fuel: bricks. But making bricks is not neat. It is messy and backbreaking. In Bangladesh, most bricks are manually made from mud, and then burnt in kilns. Workers have to use hammers to break up tons of coal every day. Then they carry the coal on their shoulders to the ovens used to fire bricks. There are more than 4,500 traditional kilns in Bangladesh that operate this way.

The country’s capital, Dhaka, is surrounded by more than 1,200 kilns. Most kilns operate only 6 months during the year (between November and April). Because more than 90% are located in low-lying areas which experience flooding during the rainy season. During the 6 months of operation, Dhaka becomes one of the most polluted cities in the world. Every day, the chimneys blow black smoke that clouds the city’s sky. The smoke is dense and contains fine particulates, which are very damaging to health. They cause no less than 20 percent of the premature deaths related to urban air pollutionin Dhaka.

How long can the country afford to make bricks in this way? The current status is by no means sustainable. To make 100,000 bricks, one needs to burn 20 tons of coal, which has high sulfur content. China, the world’s leading brick producer, uses only 6 tons of coal to make the same amount of bricks. China’s experience suggests that adopting cleaner and more energy-efficient technologies is key to success.